NFPA 16-1999 Standard for the Installation of Deluge Foam-Water Sprinkler Systems.
1-4.3 Systems shall deliver foam to the hazards they protect for a specified period at given densities, either prior to water discharge or following water discharge, depending upon sys- tem design purpose. 1-4.4 Following completion of discharge of foam solution to the hazards protected, foam-water sprinkler and spray systems shall discharge water until manually shut off. 1-4.5* Authorities having jurisdiction shall be consulted as to the means by which a reserve supply of foam concentrate shall be made available. The reserve supply shall be listed for use with system components. (See Section 2-3.) 1-4.6* Wet pipe foam-water systems shall be preprimed with foam-water solution. Exception: Systems shall not be required to be preprimed where recom- mended by the foam concentrate manufacturer and where approved by the authority having jurisdiction. 1-5 Applicability. 1-5.1* Foam-water sprinkler and spray systems shall discharge foam solution or water from the same discharge devices. Because of this dual extinguishing agent discharge character- istic, these systems shall be selectively applicable to combina- tion Class A and Class B hazards.
1-5.2 Foam-water deluge systems are applicable to the protec- tion of two-dimensional flammable liquid hazards. They shall be permitted to be used for any of the following purposes or combinations thereof: (a) Extinguishment. The primary purpose of such systems is the extinguishment of fire in the protected hazard. For this purpose, foam-solution discharge densities shall be provided by system design, use of selected discharge devices, and provi- sion of supplies of water at required pressures to accomplish the system design. Foam-discharge rates shall be able to pro- vide required rates of water discharge from the system until shut off during the design period and following depletion of foam concentrate supplies. (b) Prevention. Prevention of fire in the protected hazard is a supplemental feature of such systems. Manual operation of a system to discharge foam or water selectively from the dis- charge devices in case of accumulations of hazardous materi- als from spills in such occupancies as garages, aircraft hangars, petrochemical plants, paint and varnish plants, or from other causes in the protected area, will afford protection against ignition, pending clean-up measures. In such cases, manual system operation provides foam coverage in the area with water discharge manually available. (c) Control and Exposure Protection. Control of fire to allow controlled burning of combustible materials where extin- guishment is not possible and exposure protection to reduce heat transfer from an exposure fire can be accomplished by water spray or foam, or both, from these special systems. The degree of accomplishment is related strongly to the fixed dis- charge densities provided by the system design.NFPA 16 pdf download.